The benefits seen on bone mineral density (BMD) and fracture incidence reduction with abaloparatide (Tymlos) treatment for all postmenopausal women in the ACTIVE trial and its extension phase also were seen among the oldest members of the study cohort (ages ≥80), a post-hoc analysis found.
The Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE) trial was an international randomized study that compared subcutaneous injections of abaloparatide, 80 µg daily, with subcutaneous teriparatide, 20 µg daily, and placebo for 18 months in almost 2,500 postmenopausal women. In the ACTIVExtend phase, all patients received alendronate 70 mg weekly through month 43.
“Efficacy and safety information on pharmacological treatments to prevent fractures is sparse in older patients, who are often excluded from clinical trials. Thus, it is important to understand the efficacy and safety of osteoporosis treatments in this population,” said Felicia Cosman, MD, of Columbia University in New York City, during a poster session at the American Society for Bone and Mineral Research annual meeting.
“Fractures are particularly common among older women, and the consequences take away from the quality and quantity of life in this group,” she told MedPage Today.
Abaloparatide is a selective activator of the parathyroid 1 receptor signaling pathway that is associated with increased bone formation. It was approved by the FDA in April 2017 for the treatment of postmenopausal osteoporosis.
A previous post-hoc analysis of ACTIVE participants in the placebo-controlled phase found that the efficacy and safety of abaloparatide among women, ages ≥80, were similar to what was seen in the overall study population.
The current analysis followed those 56 women whose mean age was 81.8 at baseline through an additional 24 months, during which all received alendronate, 70 mg weekly.
Among those who had initially been randomized to receive placebo, 18.5% had at least one prior nonvertebral fracture within the previous 5 years, as did 17.2% of those initially given abaloparatide. For prevalent vertebral fractures at baseline, the corresponding numbers were 18.5% and 41.4%, respectively.
During the 24-month follow-up phase when all patients were receiving only alendronate, the fracture rates among the age >80 subgroup were low. Among those who had initially received placebo or abaloparatide, respectively, the rates subsequent fractures were:
- New vertebral fracture: 4% vs 0%
- Nonvertebral fractures: 7.4% vs 4.2%
- Clinical fractures: 7.4% vs 4.2%
- Major osteoporotic fractures: 3.7% vs 0%
BMD at the total hip, femoral neck, and lumbar spine increased significantly more in the group that had initially received abaloparatide at all time points except for total hip at month 6 and femoral neck at month 12.
During the extension phase, 81.5% of the 27 age >80 patients who had initially received placebo reported any adverse event, as did 78.6% of those who had initially been given abaloparatide. For serious adverse events, the numbers were 11% and 14.3%, and for adverse events leading to discontinuation, the numbers were 7.4% and 3.6%. No adverse events resulted in death.
The specific adverse events in the placebo versus abaloparatide groups included arthralgias (11.1% vs 7.1%), back pain (7.4% vs 10.7%), dizziness (11.1% vs 3.6%), dyspepsia (3.7% vs 10.7%), and hypertension (11.1% vs 3.6%).
“Now we have data to suggest that when treating older patients with a drug like Tymlos, we should expect to get very good results,” Cosman concluded.
The study was funded by Radius Health. Some co-authors are company employees.
Cosman dislcosed no relevant relationships with industry. Some co-authors disclosed relevant relationships with the NIH, Radius Health, Amgen, Eli Lilly, Merck, and Tarsa.
Primary Source
American Society for Bone and Mineral Research
